Electrical power may be generated by a variety of technologies implementing a variety of physical principles. One physical principle used to generate power is electromagnetic induction. One implementation of electromagnetic induction is a linear alternator, which is typically arranged so that a permanent magnet oscillates linearly along the central axis of a wound wire coil to induce an electromotive force in the wire coil. When connected to a load, the electrical current may be harnessed to provide electrical power. While linear alternators are practical and efficient, such arrangements typically emit an electromagnetic field that is generated by the magnets and coil of the linear alternator. Depending on the implementation, external electromagnetic fields are undesirable because such fields create an undesirable environment. Specifically, electromagnetic fields may interfere with sensitive instrumentation situated near a linear alternator. Therefore, linear alternators are not practical for implementations where electrical power generating equipment must be located near instrumentation that is sensitive to electromagnetic emissions.
In the prior art, shielding techniques have been used to limit interference from electromagnetic fields. Such shielding techniques typically include surrounding a linear alternator with metal sheeting or plating in an attempt to contain electromagnetic interference. Such techniques may substantially add to the weight of a linear alternator and make the alternator impractical for weight sensitive applications. In addition, shielding techniques also may create thermal management problems for any equipment that is being shielded, along with any equipment situated near the shielded equipment.
Because of the limitations of the prior art, there exists a need for novel apparatus and methods for mitigating electromagnetic interference emitting from linear alternators.